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Topic: Autobox change-up speed (Read 564 times) |
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Neil W
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Posts: 148
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Autobox change-up speed
« on: Apr 17th, 2005, 1:53pm » |
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The other day I used kickdown whilst in economy mode to overtake some slow(ish) cars and noticed that it didn't change up a gear until about 6,000rpm (at erm 95mph  ). In the past this has only happened in sport mode, and in economy it used to change up at much lower revs.
Do I have a problem, and if so how do I fix it?
Autobox is a Ford fitted recon with about 42,000 miles use. Changes very smoothly up or down, but when stationary there is a slight pause and jerk on engaging drive or reverse. Car has 92,000 on the clock. Owned the car from new.
Neil W.
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1998 Scorpio Ultima Cosworth facelift saloon, reg S896VOG. Sold Feb 2010. Now own Mercedes-Benz E320 CDi.
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scorpio_man
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Ford Kuga awd
Posts: 5654
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Re: Autobox change-up speed
« Reply #1 on: Apr 17th, 2005, 2:06pm » |
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hi there
kick down is controlled by the ecu from various sensors. do you have an obd-2 lead or multi-meter? check the throttle postion sensor for a 'nice flow'. on obd-2 it starts at about 16% up to 80%+. fully open (kick down) is at about 93%.
the car's properly just got a bit confused, and held the gear at bit longer than usual because your foot didn't lift off a bit.
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mr._floppy
Junior Member
Posts: 100
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Re: Autobox change-up speed
« Reply #2 on: Apr 17th, 2005, 2:08pm » |
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WOW! 6000 rpm, I don't think mine would get to that speed.
If you ease off on the pedal it should pop itself into overdrive eventually , but if you've got it to the floor, you,re asking the engine to give its maximum power , and that's what it's doing.
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Neil W
Full Member
Posts: 148
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Re: Autobox change-up speed
« Reply #3 on: Apr 19th, 2005, 11:34am » |
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Thanks for the comments, guys. Yep, the 24v will reach 6000 revs all too easily but even in second gear that is about 95mph.
I understand that easing off the accelerator will induce an upward gear change, but my point was that the speed at which change up occurs in economy kickdown mode has altered. I therefore wondered if this was telling me something. Unfortunately I don't have an OBD lead, and woudn't know how to use it if I had it  !
As far as I know the MAF has never been cleaned, not even by the FMD during services (at least it is not mentioned on work sheets), so would that be a possible cause of the problem? Cleaning MAF's seems to have become "the thing to do" on this site, and the apparent solution to many problems, but I prefer to leave well alone unless it is absolutely the right thing to do.
Regards,
Neil W.
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1998 Scorpio Ultima Cosworth facelift saloon, reg S896VOG. Sold Feb 2010. Now own Mercedes-Benz E320 CDi.
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Thunderchild
Full Member
My other car's an Aprilia
Posts: 199
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Re: Autobox change-up speed
« Reply #5 on: Apr 20th, 2005, 12:37pm » |
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Hi there,
Got to say that my 24v does exactly the same thing and always has. The point is that whether you are in sports or economy mode makes no difference when your foot is flat on the floor... the car is going to accelerate as hard as it can all the way up through the rev range.
When you have the joy of acceleration like that, does it really matter if it holds the gear a bit longer ?
HTH
Thunderchild
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Neil W
Full Member
Posts: 148
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Re: Autobox change-up speed
« Reply #6 on: Apr 22nd, 2005, 1:12pm » |
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Thanks again, guys.
Comment about flooring the gas pedal telling the engine to go to max revs before changeup irrespective of mode had't occurred to me before  .
And I guess I'll have to clean the MAF afterall , as one way or another it should either solve the problem or eliminate the MAF itself as a contributor to the problem.
Regards,
Neil W.
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1998 Scorpio Ultima Cosworth facelift saloon, reg S896VOG. Sold Feb 2010. Now own Mercedes-Benz E320 CDi.
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mr._floppy
Junior Member
Posts: 100
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Re: Autobox change-up speed
« Reply #7 on: Apr 22nd, 2005, 11:39pm » |
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Actually, I find the kickdown facility rather annoying at times, when you are tootling along at 65 on the motorway and need just a tad more revs to leisurely overtake a lorry , the merest touch on the accelerator causes the gear box to drop a cog . Completely unecessary ( or maybe the kickdown needs adjustment ).
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scorpio_man
Administrator
Ford Kuga awd
Posts: 5654
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Re: Autobox change-up speed
« Reply #8 on: Apr 23rd, 2005, 7:30am » |
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hi there
in that situation, it's better to switch o/d off. the revs will rise about 500 rpm, make a perfect over taking manoeuvre.
hth
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